/*
 * Copyright (C) 2013 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.bluetooth.le;

import java.util.List;
import java.util.UUID;

import com.ajie.slimming.util.Util;

import android.app.Service;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothGatt;
import android.bluetooth.BluetoothGattCallback;
import android.bluetooth.BluetoothGattCharacteristic;
import android.bluetooth.BluetoothGattDescriptor;
import android.bluetooth.BluetoothGattService;
import android.bluetooth.BluetoothManager;
import android.bluetooth.BluetoothProfile;
import android.content.Context;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;
import android.util.Log;

/**
 * Service for managing connection and data communication with a GATT server
 * hosted on a given Bluetooth LE device.
 */
public class BluetoothLeService extends Service
{
    private final static String TAG = BluetoothLeService.class.getSimpleName();
    
    private BluetoothManager mBluetoothManager;
    
    private BluetoothAdapter mBluetoothAdapter;
    
    private String mBluetoothDeviceAddress;
    
    private BluetoothGatt mBluetoothGatt;
    
    private int mConnectionState = STATE_DISCONNECTED;
    
    private static final int STATE_DISCONNECTED = 0;
    
    private static final int STATE_CONNECTING = 1;
    
    private static final int STATE_CONNECTED = 2;
    
    public final static String ACTION_GATT_CONNECTED = "com.example.bluetooth.le.ACTION_GATT_CONNECTED";
    
    public final static String ACTION_GATT_DISCONNECTED = "com.example.bluetooth.le.ACTION_GATT_DISCONNECTED";
    
    public final static String ACTION_GATT_SERVICES_DISCOVERED = "com.example.bluetooth.le.ACTION_GATT_SERVICES_DISCOVERED";
    
    public final static String ACTION_DATA_AVAILABLE = "com.example.bluetooth.le.ACTION_DATA_AVAILABLE";
    
    public final static String EXTRA_DATA = "com.example.bluetooth.le.EXTRA_DATA";
    
    public final static UUID UUID_HEART_RATE_MEASUREMENT = UUID.fromString(SampleGattAttributes.HEART_RATE_MEASUREMENT);
    
    // Implements callback methods for GATT events that the app cares about. For
    // example,
    // connection change and services discovered.
    private final BluetoothGattCallback mGattCallback = new BluetoothGattCallback()
    {
        @Override
        public void onConnectionStateChange(BluetoothGatt gatt, int status,
                int newState)
        {
            String intentAction;
            if (newState == BluetoothProfile.STATE_CONNECTED)
            {
                intentAction = ACTION_GATT_CONNECTED;
                mConnectionState = STATE_CONNECTED;
                broadcastUpdate(intentAction);
                Log.i(TAG, "Connected to GATT server.");
                // Attempts to discover services after successful connection.
                Log.i(TAG, "Attempting to start service discovery:"
                        + mBluetoothGatt.discoverServices());
                
            }
            else if (newState == BluetoothProfile.STATE_DISCONNECTED)
            {
                intentAction = ACTION_GATT_DISCONNECTED;
                mConnectionState = STATE_DISCONNECTED;
                Log.i(TAG, "Disconnected from GATT server.");
                broadcastUpdate(intentAction);
            }
        }
        
        @Override
        public void onServicesDiscovered(BluetoothGatt gatt, int status)
        {
            if (status == BluetoothGatt.GATT_SUCCESS)
            {
                broadcastUpdate(ACTION_GATT_SERVICES_DISCOVERED);
            }
            else
            {
                Log.w(TAG, "onServicesDiscovered received: " + status);
            }
        }
        
        @Override
        public void onCharacteristicRead(BluetoothGatt gatt,
                BluetoothGattCharacteristic characteristic, int status)
        {
            Log.i(TAG, "onCharacteristicRead status " + status);
            if (status == BluetoothGatt.GATT_SUCCESS)
            {
                broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
            }
        }
        
        @Override
        public void onCharacteristicChanged(BluetoothGatt gatt,
                BluetoothGattCharacteristic characteristic)
        {
            Log.i(TAG, "onCharacteristicChanged");
            broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
        }
        
        @Override
        public void onCharacteristicWrite(BluetoothGatt gatt,
                BluetoothGattCharacteristic characteristic, int status)
        {
        };
    };
    
    private void broadcastUpdate(final String action)
    {
        final Intent intent = new Intent(action);
        sendBroadcast(intent);
    }
    
    private void broadcastUpdate(final String action,
            final BluetoothGattCharacteristic characteristic)
    {
        final Intent intent = new Intent(action);
        // For all other profiles, writes the data formatted in HEX.
        final byte[] data = characteristic.getValue();
        if (data != null && data.length > 0)
        {
            //            final StringBuilder stringBuilder = new StringBuilder(data.length);
            //            for (byte byteChar : data)
            //                stringBuilder.append(String.format("%02X ", byteChar));
            //            Log.d(TAG, stringBuilder.toString());
            Log.d(TAG, new String(data));
            Log.d(TAG, Util.printHexString(data));
            System.out.println("--->>   "+Util.printHexString(data));
            intent.putExtra(EXTRA_DATA, Util.printHexString(data));
        }
        sendBroadcast(intent);
    }
    
    public class LocalBinder extends Binder
    {
        public BluetoothLeService getService()
        {
            return BluetoothLeService.this;
        }
    }
    
    @Override
    public IBinder onBind(Intent intent)
    {
        return mBinder;
    }
    
    @Override
    public boolean onUnbind(Intent intent)
    {
        // After using a given device, you should make sure that
        // BluetoothGatt.close() is called
        // such that resources are cleaned up properly. In this particular
        // example, close() is
        // invoked when the UI is disconnected from the Service.
        close();
        return super.onUnbind(intent);
    }
    
    private final IBinder mBinder = new LocalBinder();
    
    /**
     * Initializes a reference to the local Bluetooth adapter.
     * 
     * @return Return true if the initialization is successful.
     */
    public boolean initialize()
    {
        // For API level 18 and above, get a reference to BluetoothAdapter
        // through
        // BluetoothManager.
        if (mBluetoothManager == null)
        {
            mBluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
            if (mBluetoothManager == null)
            {
                Log.e(TAG, "Unable to initialize BluetoothManager.");
                return false;
            }
        }
        
        mBluetoothAdapter = mBluetoothManager.getAdapter();
        if (mBluetoothAdapter == null)
        {
            Log.e(TAG, "Unable to obtain a BluetoothAdapter.");
            return false;
        }
        
        return true;
    }
    
    /**
     * Connects to the GATT server hosted on the Bluetooth LE device.
     * 
     * @param address
     *            The device address of the destination device.
     * 
     * @return Return true if the connection is initiated successfully. The
     *         connection result is reported asynchronously through the
     *         {@code BluetoothGattCallback#onConnectionStateChange(android.bluetooth.BluetoothGatt, int, int)}
     *         callback.
     */
    public boolean connect(final String address)
    {
        if (mBluetoothAdapter == null || address == null)
        {
            Log.w(TAG,
                    "BluetoothAdapter not initialized or unspecified address.");
            return false;
        }
        
        // Previously connected device. Try to reconnect.
        if (mBluetoothDeviceAddress != null
                && address.equals(mBluetoothDeviceAddress)
                && mBluetoothGatt != null)
        {
            Log.d(TAG,
                    "Trying to use an existing mBluetoothGatt for connection.");
            if (mBluetoothGatt.connect())
            {
                mConnectionState = STATE_CONNECTING;
                return true;
            }
            else
            {
                return false;
            }
        }
        
        final BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(address);
        if (device == null)
        {
            Log.w(TAG, "Device not found.  Unable to connect.");
            return false;
        }
        // We want to directly connect to the device, so we are setting the
        // autoConnect
        // parameter to false.
        mBluetoothGatt = device.connectGatt(this, false, mGattCallback);
        Log.d(TAG, "Trying to create a new connection.");
        mBluetoothDeviceAddress = address;
        mConnectionState = STATE_CONNECTING;
        return true;
    }
    
    /**
     * Disconnects an existing connection or cancel a pending connection. The
     * disconnection result is reported asynchronously through the
     * {@code BluetoothGattCallback#onConnectionStateChange(android.bluetooth.BluetoothGatt, int, int)}
     * callback.
     */
    public void disconnect()
    {
        if (mBluetoothAdapter == null || mBluetoothGatt == null)
        {
            Log.w(TAG, "BluetoothAdapter not initialized");
            return;
        }
        mBluetoothGatt.disconnect();
    }
    
    /**
     * After using a given BLE device, the app must call this method to ensure
     * resources are released properly.
     */
    public void close()
    {
        if (mBluetoothGatt == null)
        {
            return;
        }
        mBluetoothGatt.close();
        mBluetoothGatt = null;
    }
    
    /**
     * Request a read on a given {@code BluetoothGattCharacteristic}. The read
     * result is reported asynchronously through the
     * {@code BluetoothGattCallback#onCharacteristicRead(android.bluetooth.BluetoothGatt, android.bluetooth.BluetoothGattCharacteristic, int)}
     * callback.
     * 
     * @param characteristic
     *            The characteristic to read from.
     */
    public void readCharacteristic(BluetoothGattCharacteristic characteristic)
    {
        if (mBluetoothAdapter == null || mBluetoothGatt == null)
        {
            Log.w(TAG, "BluetoothAdapter not initialized");
            return;
        }
        mBluetoothGatt.readCharacteristic(characteristic);
    }
    
    /**
     * Enables or disables notification on a give characteristic.
     * 
     * @param characteristic
     *            Characteristic to act on.
     * @param enabled
     *            If true, enable notification. False otherwise.
     */
    public void setCharacteristicNotification(
            BluetoothGattCharacteristic characteristic, boolean enabled)
    {
        if (mBluetoothAdapter == null || mBluetoothGatt == null)
        {
            Log.w(TAG, "BluetoothAdapter not initialized");
            return;
        }
        mBluetoothGatt.setCharacteristicNotification(characteristic, enabled);
        
        // This is specific to Heart Rate Measurement.
        if (UUID_HEART_RATE_MEASUREMENT.equals(characteristic.getUuid()))
        {
            BluetoothGattDescriptor descriptor = characteristic.getDescriptor(UUID.fromString(SampleGattAttributes.CLIENT_CHARACTERISTIC_CONFIG));
            descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
            mBluetoothGatt.writeDescriptor(descriptor);
        }
    }
    
    /**
     * Retrieves a list of supported GATT services on the connected device. This
     * should be invoked only after {@code BluetoothGatt#discoverServices()}
     * completes successfully.
     * 
     * @return A {@code List} of supported services.
     */
    public List<BluetoothGattService> getSupportedGattServices()
    {
        if (mBluetoothGatt == null)
            return null;
        
        return mBluetoothGatt.getServices();
    }
}
